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[Intro]: Audio and mix– Geosmin in the news - Tens of thousands of upstatehomeowners may have noticed a funny taste or smell in their water recently.

Douglas: There's something about clean water that engages our aesthetic instinct.When you pour nice cold glass of water from the tap, you expect to be clean, and clearand well, certainly not to have any unpleasant odor. But if it does, humans are able todetect it at unbelievably low levels.

[Intro-Reprise]: Audio and mix– Geosmin in the news - You may have noticed thewater from you tap doesn't smell or taste right. Music: It tastes like dirt, like you smelldirt. An organic compound called GEOSMIN was likely washed into the lake.

Douglas: Today on our program Geosmin in South Carolina's waters, where it comesfrom and will it harm you. I'm Ray Douglas and this is Water Science for a ChangingWorld.

Douglas: Celeste Journey is Water Quality Specialist for the South Carolina WaterScience Center. Celeste thanks for joining us today.

Journey: Oh it's great to be here.

Douglas: Basically what is Geosmin?

Journey: If you have ever gone to a garden that has been freshly tilled and you grab ahandful of the freshly tilled earth and take a smell and you smell that earthy smell,that's actually Geosmin.

Douglas: OK, so how and where does it occur?

Journey: Geosmin is naturally produced in both the soil and lakes, and reservoirs andstreams. In the soil it is often produced by a bacteria. This bacteria is calledactinomycetes.

Douglas: Ok, actinomycetes, can you expand on those, what are they?

Journey: One of the genera of actinomycetes is streptomycetes it is actually bacteriathat produces the streptomycin an antibiotic that we commonly use. But in the lakes,and rivers and streams often it's not that bacteria, but instead blue-green algae.

Douglas: Isn't blue-green algae the type of algae that you hear about in the lakewarnings in the midwest?

Journey: That's correct. These are more like the weeds of the algae community, theyare the ones that are often considered nuisance algae.

Douglas: OK, so the Geosmin, the stuff you can smell, is it harmful?

Journey: Geosmin in itself is not harmful it is simply a compound that humans candetect at very low levels. The human detection threshold is considered ten parts-pertrillion, which is a very low amount.

Douglas: OK, wait a minute. You have raised two points of concern. First the humandetection threshold is ten parts-per trillion. Can you explain just how small of anamount that actually is?

Journey: A nanogram per liter or part of per trillion is an extremely small amount, weare talking about just a drop in an olympic size swimming pool and people are able todetect it.

Douglas: Obviously that is a very low concentration and you've said that Geosmin isnot a human health threat and it is naturally occurring. So what's the problem withGeosmin?

Journey: The problem is that water treatment plants can not remove it from theirsystem, and so people start tasting this earthy taste in their drinking water and, it is nota very pleasing thing. It is more of an atheistic problem, not a harmful problem.

Douglas: Aesthetics, that can be kind of subjective. So there has to be a lot more toGeosmin than that. Why is Geosmin so important, and why is it important enough thatthe USGS would be involved?

Journey: Geosmin can co-occur with toxins, and toxins are harmful to humans. Theyare also harmful to aquatic life and they are harmful to pets who may be swimming inwater when they are present.

Douglas: So, the presence of Geosmin is sort of a warning sign. It is a symptom thatmay be more harmful bacteria could emerge. So what USGS work is being done herein South Carolina?

Journey: There's an interest to know more about Geosmin by many water utilities andspecifically in the Spartanburg area of South Carolina. A water utility wanted to knowmore about this sporadic occurrence of Geosmin in their water system.

Douglas: So what was the main reason for this study?

Journey: One of the focuses was to determine if the source of Geosmin was actuallyhappening in the lake because of production by algae, or if it was coming from thewater shed being delivered in soils with the bacteria on the soils.

Douglas: So what was the answer USGS came up with?

Journey: What we found for those reservoirs is that the source was actually occurringin the lake by algae production. Specifically by blue-green algae. There are certainspecies of blue-green algae that produce Geosmin and they also can produce toxins.

Douglas: I understand that blue-green algae at its worst can produce algal blooms,really nasty looking stuff on the surface of the water. Was that about to occur?

Journey: In the two lakes we studied this was not a problem, alga blooms were notapparent and were observed, but we did know that the blue-green algae were presentin the reservoir at the time of sampling and when Geosmin occurred.

Douglas: So were the findings helpful to the cooperator and how are they using yourfindings?

Journey: This study was very beneficial to Spartanburg Water they know now thattheir nutrient management strategies in their water shed are being very effective andthey are controlling blue-green algae occurrence in these reservoirs, and preventingthe concurrence of toxins with Geosmin occurrence.

Douglas: But again, we are talking about highly diluted concentrations. Is thereanything that we can change, is there anything that residents can do to prevent thisfrom happening?

Journey: The watershed does contribute nutrients and of course people live in thewatershed. One of the things residents within the water shed and around the lake cando to support the good water quality in Lake Bowan and reservoir number one is to:maintain their lawns effectively; reduce the amount of fertilizer applied and when theyapply it; and also making sure that their septic tanks are well maintained according tocode. This will reduce the amount of nutrients and help keep the level of nutrientsentering the lake at a low level, and provide long-term water quality in these lakes.

Douglas: Will the results from this study be the same for other lakes in SouthCarolina?

Journey: The findings from this study are unique to this reservoir and we are not reallysure how applicable this would be within other lakes in South Carolina. It definitelydoes not fit the conditions that we see in the midwestern reservoirs and it would be agreat question to try and answer to see how applicable this natural phenomenon ofGeosmin occurrence is to other reservoirs in South Carolina and in the southeast.

Douglas: Celeste, Thanks for taking time to be with us today and for all the great workyou and your team do here in South Carolina.

Journey: Thank You! I really enjoyed being here and getting a chance to get to showsome the great research we were able to do recently.

Douglas: That was Celeste Journey USGS Water Quality Specialist for the SouthCarolina Water Science Center.For more information on Geosmin visit us on the web at sc.water.usgs.gov. Click onpublications and look for fact sheet number 2009-3043.

[Close]: Audio and mix– from Geosmin in the news - You may have noticed the waterfrom you tap doesn't smell or taste quite right. The local water company says there is areason. An organic compound called GEOSMIN. It tastes like dirt, like you smell dirt.An organic compound called GEOSMIN. Tens of thousands of upstate homeownersmay have noticed a funny taste or smell in their water recently but water officials saythe water is.

Water Science for a changing world is a product of the U.S. Geological Survey's SouthCarolina Water Science Center.